1. Field of the Invention
The invention relates to an irrigation machine and particularly relates to an irrigation machine of the type which is guided to follow the course of a water supply pipe having self-closing hydrants spaced apart along the length of the pipe and by which a water distribution device such as a water gun, sprinkler or a fixed or a rotatable boom carrying sprinklers is arranged to be coupled and to be supplied with water by the hydrants in succession, thereby progressively to irrigate an area of ground as the machine travels along the course of the pipe.
2. Description of the Prior Art
Some irrigation machines of the foregoing type are guided electrically and others employ guiding wheels arranged to engage the pipe itself. Whichever method of guidance is employed it is desirable to bring the machine to a stop in a precise position to enable a connection to be made to the hydrant. An object of the invention is to provide a machine which is automatically adjusted to a precise position with respect to a hydrant to which it is to be coupled.
Hitherto irrigation machines of the foregoing type having either method of guidance have suffered from the disadvantage that the main load-carrying traction wheels of the machine run on the ground being irrigated. This factor has limited the size of the machine due to the considerable weight and thrust when a machine of this type is irrigating or requires the construction of special tracks for the traction wheels. A further object of the invention is to provide an irrigation machine of the foregoing type in which this disadvantage is avoided.
Yet another object of the invention is to provide pipe-following and automatic hydrant-engaging means for converting an irrigation machine of a type which is not automatically movable between irrigating positions into a pipe-following and hydrant-engaging machine. Another object of the invention is to provide a complete irrigating machine having pipe-following and hydrant-engaging means which is automatically adjustable relatively to the remainder of the machine when a hydrant is being engaged to enable a coupling to the hydrant to be effected, thereby enabling pipe-following and hydrant-engaging means to be used in a large and heavy irrigation machine which could not otherwise be precisely positioned with respect to a hydrant.